RDS: Modularize RDMA and TCP transports

Enable the building of transports as modules.

Also, improve consistency of Kconfig messages in relation to other
protocols, and move build dependency on IB from the RDS core code
to the rds_rdma module.
Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/Kconfig

 
 config RDS
-	tristate "Reliable Datagram Sockets (RDS) (EXPERIMENTAL)"
-	depends on INET && INFINIBAND_IPOIB && EXPERIMENTAL
-	depends on INFINIBAND && INFINIBAND_ADDR_TRANS
+	tristate "The RDS Protocol (EXPERIMENTAL)"
+	depends on INET && EXPERIMENTAL
 	---help---
-	  RDS provides reliable, sequenced delivery of datagrams
-	  over Infiniband.
+	  The RDS (Reliable Datagram Sockets) protocol provides reliable,
+	  sequenced delivery of datagrams over Infiniband, iWARP,
+	  or TCP.
+
+config RDS_RDMA
+	tristate "RDS over Infiniband and iWARP"
+	depends on RDS && INFINIBAND && INFINIBAND_ADDR_TRANS
+	---help---
+	  Allow RDS to use Infiniband and iWARP as a transport.
+	  This transport supports RDMA operations.
+
+config RDS_TCP
+	tristate "RDS over TCP"
+	depends on RDS
+	---help---
+	  Allow RDS to use TCP as a transport.
+	  This transport does not support RDMA operations.
 
 config RDS_DEBUG
-        bool "Debugging messages"
+        bool "RDS debugging messages"
 	depends on RDS
         default n
 

net/rds/Makefile

 obj-$(CONFIG_RDS) += rds.o
 rds-y :=	af_rds.o bind.o cong.o connection.o info.o message.o   \
 			recv.o send.o stats.o sysctl.o threads.o transport.o \
-			loop.o page.o rdma.o \
-			rdma_transport.o \
+			loop.o page.o rdma.o
+
+obj-$(CONFIG_RDS_RDMA) += rds_rdma.o
+rds_rdma-objs :=	rdma_transport.o \
 			ib.o ib_cm.o ib_recv.o ib_ring.o ib_send.o ib_stats.o \
 			ib_sysctl.o ib_rdma.o \
 			iw.o iw_cm.o iw_recv.o iw_ring.o iw_send.o iw_stats.o \
 			iw_sysctl.o iw_rdma.o
 
+
+obj-$(CONFIG_RDS_TCP) += rds_tcp.o
+rds_tcp-objs :=		tcp.o tcp_connect.o tcp_listen.o tcp_recv.o \
+			tcp_send.o tcp_stats.o
+
 ifeq ($(CONFIG_RDS_DEBUG), y)
 EXTRA_CFLAGS += -DDEBUG
 endif

net/rds/af_rds.c

@@ -39,7 +39,6 @@
 
 #include "rds.h"
 #include "rdma.h"
-#include "rdma_transport.h"
 
 /* this is just used for stats gathering :/ */
 static DEFINE_SPINLOCK(rds_sock_lock);
@@ -509,7 +508,6 @@ static void rds_sock_info(struct socket *sock, unsigned int len,
 
 static void __exit rds_exit(void)
 {
-	rds_rdma_exit();
 	sock_unregister(rds_family_ops.family);
 	proto_unregister(&rds_proto);
 	rds_conn_exit();
@@ -549,14 +547,8 @@ static int __init rds_init(void)
 	rds_info_register_func(RDS_INFO_SOCKETS, rds_sock_info);
 	rds_info_register_func(RDS_INFO_RECV_MESSAGES, rds_sock_inc_info);
 
-	/* ib/iwarp transports currently compiled-in */
-	ret = rds_rdma_init();
-	if (ret)
-		goto out_sock;
 	goto out;
 
-out_sock:
-	sock_unregister(rds_family_ops.family);
 out_proto:
 	proto_unregister(&rds_proto);
 out_stats:

net/rds/rdma_transport.c

@@ -203,6 +203,7 @@ int __init rds_rdma_init(void)
 out:
 	return ret;
 }
+module_init(rds_rdma_init);
 
 void rds_rdma_exit(void)
 {
@@ -211,4 +212,9 @@ void rds_rdma_exit(void)
 	rds_ib_exit();
 	rds_iw_exit();
 }
+module_exit(rds_rdma_exit);
+
+MODULE_AUTHOR("Oracle Corporation <rds-devel@oss.oracle.com>");
+MODULE_DESCRIPTION("RDS: IB/iWARP transport");
+MODULE_LICENSE("Dual BSD/GPL");